Dual-igniter airbag control switch

ABSTRACT

A dual-igniter airbag control switch is provided for a motor vehicle airbag system having a module with a plurality of igniters for causing an airbag to inflate, a diagnostic monitor that determines if a collision is occurring and initiates the igniters, and first and second wires extending between each of the igniters and the monitor for conveying signals between the module and the monitor. The control switch comprises a manually operable switch having portions connected to each of the first wires, for selectively providing continuity in the first wires between the monitor and each of the igniters while in an on position and breaking continuity of the first wires between the monitor and each of the igniters while in an off position. A resistor is connected to each of the second wires and connected to the switch, so that while in the off position, the switch places the resistors in series between the first and second wires and the monitor, each of the resistors having an impedance similar to that of one of the igniters, so as to provide a false indication to the monitor that the continuity exists with the igniters while the switch is in the off position.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a Continuation of pending U.S. patentapplication Ser. No. 09/487,532, filed Jan. 19, 2000 entitled“DUAL-IGNITER AIRBAG CONTROL SWITCH,” and is related to, and claims thebenefits of priority from, U.S. Provisional Patent Application SerialNo. 60/116,554, entitled “DUAL-IGNITER AIRBAG CONTROL SWITCH,” filedJan. 21, 1999.

TECHNICAL FIELD OF THE INVENTION

[0002] This invention relates in general to electrical control systemsand in particular to devices for controlling automotive supplementaryrestraint systems.

BACKGROUND OF THE INVENTION

[0003] Since the early 1990's, automobile manufacturers selling cars inthe United States have been required to equip the cars withsupplementary restraint systems (airbags). One or more airbags arestored in a forward position from the front seated passengers. Thevehicle's computer system monitors activity to the automobile andinitiates necessary deployments of the airbag by sending signals throughthe circuitry to the airbag module. By design, the rapid inflation ofthe airbag protects the passenger from contact with the vehicle'ssteering wheel, dashboard, windshield, or other components.

[0004] One problem associated with these airbags is the growing safetyconcerns for smaller-sized adults, children seated in the frontpassenger seat of the vehicle and children in child safety seats securedin the front passenger seat of the vehicle. During the rapid and violentinflation, the airbag has potential to do harm to these particularclasses of passengers.

[0005] Automotive manufacturers have offered switches as an option fordisabling a single airbag having a single igniter. Airbags havingmultiple stage igniters have now been introduced. A multiple stageigniter has two igniters. At a low speed collision, only one of theigniters may ignite to inflate the airbag, while at higher speeds, bothigniters actuate to inflate the bag. The single igniter inflates theairbag with less force than the two combined. To applicant's knowledge,prior to applicant's invention, manufacturers did not offer disablingswitches for dual stage igniters.

SUMMARY OF THE INVENTION

[0006] In this invention, a switch allows a request from the vehicle'scomputer system to inflate the airbags to be over-ridden and the airbagprevented from inflating. Similarly, the switch can be positioned tohave the vehicle computer system and airbag modules work withoutinterruption and function as normal. In the preferred embodiment, thevehicle's original circuit between the computer system and the airbagmodule is broken. A switching device is connected in this created gap,causing the vehicle's circuit to run through the switching device. Theswitching device allows an operator to select whether the computersystem's signals will pass through to the airbag module uninterrupted orbe altered. The device may work as an over-ride of the computer'srequest by the operator selected request. The switching device workswith more than one airbag, and it also is operative with dual stagemodules.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007]FIG. 1 is a schematic front view of one embodiment of a switchconstructed in accordance with the invention.

[0008]FIG. 2 is an electrical diagram showing the switch of FIG. 1connected to an airbag.

DETAILED DESCRIPTION OF THE INVENTION AND BEST MODE

[0009] Referring to FIG. 1, a device 11 for controlling the deploymentof an automotive supplementary restraint system (airbag) is shown.Device 11 has a rectangular housing 13 with a two-position (“on” and“off”) key switch 15 on a front face. A removable key 17 is provided foractuating switch 15. Each position of switch 15 has a light emittingdiode (LED) 19, 21 for visual confirmation of the position selected.Although switch 15 only has two positions in the embodiment shown, itcould have other positions depending upon the configuration of theairbag system.

[0010] Referring now to FIG. 2, an electrical diagram for connectingswitch 11 to a single airbag module 101 having two igniters 103, 105 isshown. Igniters 103, 105 may be used for various reasons includingdeployment of module 101 at different velocities. Typically, a sensorwill determine the severity of the impact of the vehicle. If the impactis less severe, only one of the igniters 103, 105 ignites to inflateairbag 101. If the impact is more severe, both igniters 103, 105 igniteto inflate airbag 101. Each igniter 103, 105 is connected through a pairof wires 111, 113 and 115, 117, respectively, to a diagnostic monitor orcontroller 1 19. Monitor 1 19 is the vehicle's system computer thatmonitors the status of module 101 among other functions. Without device11 (FIG. 1), module 101, igniters 103, 105, and monitor 119 would beconnected directly to one another through wires 111-117. However, withdevice 11, wires 111 and 115 are interrupted at breaks 121, 123,respectively, and connected to device 11.

[0011] In the embodiment shown in FIG. 2, switch 15 is a conventionaltriple-pole, double-throw switch. Switch 15 has a first pole 131 withleads or wires 133, 135, 137. Wires 133, 135 are connected to break 121in wire 111, and wire 137 is connected to wire 113. Wire 137 has aresistor 139 that places a load that is the same as the impedance of theairbag module 101 so that the diagnostic monitor 119 does not register afault. Wire 137 also has a fuse 141 in series with resistor 139. Switch15 has a second pole 143 with wires 145, 147, 149. Wires 145, 147 areconnected to break 123 in wire 115, and wire 149 is connected to wire117. Like wire 137, wire 149 has a resistor 151 in series with a fuse153. Switch 15 has a third pole 155 with wires 157, 159, 161. Each wires157, 159 has an LED 19, 21, respectively, which are connected inparallel to a 12-volt DC battery 163. Wire 161 is connected to ground.Preferably, wires 133, 135, 137, 145, 147, 149, 157, 159, 161 exit thehousing 13 through the back face.

[0012] In operation, device 11 may be turned off to prevent airbagmodule 101 from deploying in the event of a collision, or turned on toallow module 101 to deploy. When device 11 is “on” (FIG. 2), poles 131,143, 155 are simultaneously thrown or actuated to the upper positions.This allows the circuit to be completed between module 101 and monitor119 through wires 111, 133, 135 and wires 115, 145, 147. At the sametime, pole 155 activates LED 19 to emit a green light to opticallyinform the user that the airbag 101 is active and ready to deploy.

[0013] When device 11 is “off” (not shown), poles 131, 143, 155 aresimultaneously thrown to the lower positions. This interrupts thecircuit between module 101 and monitor 119 at breaks 121, 123. Pole 155activates LED 21 to emit a yellow light to inform the user that airbag101 is inactive and will not deploy.

[0014] While the invention has been shown or described in only one ofits forms, it should be apparent to those skilled in the art that it isnot so limited, but is susceptible to various changes without departingfrom the scope of the invention. For example, the device shown anddescribed could be easily reconfigured for multiple airbag modules,multiple igniters or any combinations thereof.

What is claimed is:
 1. In a motor vehicle airbag system, having a modulewith a plurality of igniters for causing an airbag to inflate, adiagnostic monitor that determines if a collision is occurring andinitiates the igniters, and first and second wires extending betweeneach of the igniters and the monitor for conveying signals between themodule and the monitor, the improvement comprising: a manually operableswitch having portions connected to each of the first wires, forselectively providing continuity in the first wires between the monitorand each of the igniters while in an on position and breaking continuityof the first wires between the monitor and each of the igniters while inan off position; and a resistor connected to each of the second wiresand connected to the switch, so that while in the off position, theswitch places the resistors in series between the first and second wiresand the monitor, each of the resistors having an impedance similar tothat of one of the igniters, so as to provide a false indication to themonitor that the continuity exists with the igniters while the switch isin the off position.
 2. The airbag system according to claim 1, furthercomprising an optical signal device connected to the switch thatprovides an optical signal while the switch is in the off position. 3.The airbag system according to claim 1, wherein the switch portionscomprise a pole for each of the first wires, the poles being movable inunison when the switch moves between the on and off positions.
 4. Theairbag system according to claim 1, further comprising: a housingadapted to be mounted within a motor vehicle, the switch and theresistors being located within the housing, the switch having a manualengagement portion located on an exterior of the housing for engagementby a user.
 5. The airbag system according to claim 1, furthercomprising: a housing adapted to be mounted within a motor vehicle, theswitch and the resistors being located within the housing, the switchhaving a manual engagement portion located on an exterior of the housingfor engagement by a user; and an optical device connected to the switchthat provides an optical signal while the switch is in the off position,the optical signal device being mounted to the exterior of the housing.6. In a motor vehicle airbag system, having a module with a plurality ofigniters for causing an airbag to inflate, a diagnostic monitor thatdetermines if a collision is occurring and initiates the igniters, andfirst and second wires extending between each of the igniters and themonitor for conveying signals between the module and the monitor, theimprovement comprising: a break in each of the first wires, interruptingcontinuity between the monitor and each of the igniters; a housingadapted to be mounted in a passenger compartment of the motor vehicle; apair of leads for each of the first wires, the leads of each pair havingends connected to one of the first wires on opposite sides of thebreaks, each pair of leads extending into the housing; a manuallyoperable switch mounted in the housing and having a manual engagementactuator on an exterior of the housing, the switch having a pole foreach igniter, each of the poles being connected to one of the leads ofeach of the pairs, each of the poles having an on position that connectsthe leads of each of the pairs together for providing continuity betweenthe monitor and each of the igniters, each of the poles having an offposition that breaks the connection between the leads of each of thepairs; a resistor mounted in the housing for each of the igniters, eachof the resistors being electrically connected to each of the secondwires and connected to the switch, so that while in an off position, thepoles place the resistors in a series between the first and second wiresand the monitor, each of the resistors having an impedance similar tothat of one of the igniters so as to avoid a default signal by themonitor while the switch is in the off position.
 7. The airbag systemaccording to claim 6, further comprising: an optical signal deviceconnected to the switch that provides an optical signal while the switchis in the off position, the optical signal device being mounted to theexterior of the housing.
 8. The airbag system according to claim 7,wherein the switch has three poles and is a double-throw.
 9. A method ofcontrolling airbag deployment of a motor vehicle airbag system having amodule with a plurality of igniters for causing an airbag to inflate, adiagnostic monitor that determines if a collision is occurring andinitiates the igniters, and first and second wires extending betweeneach of the igniters and the monitor for conveying signals between themodule and the monitor, the method comprising: severing each of thefirst wires between the igniters and the monitor, creating a pair ofends for each of the first wires; connecting a portion of a manuallyoperable switch between the ends of each of the first wires; connectingone side of a resistor to each of the second wires and the other side tothe switch, each of the resistors having an impedance similar to that ofone of the igniters; placing the switch in an on position, providingcontinuity in the first wires between the monitor and each of theigniters; then placing the switch in an off position, breakingcontinuity in the first wires between the monitor and each of theigniters and simultaneously placing the resistors in series between thefirst and second wires and the monitor, each of the resistors having animpedance similar to that of one of the igniters, so as to provide afalse indication to the monitor that continuity exists with the igniterswhile the switch is in the off position.
 10. The method as recited inclaim 9, further comprising: providing an illuminated signal while theswitch is in the off position.